Simultaneous propagation of two Dyakonov-Tamm waves guided by the planar interface created in a chiral sculptured thin film by a sudden change of vapor flux direction

While growing a chiral sculptured thin film by physical vapor deposition, a sudden change in the direction of the vapor flux creates a plane of discontinuity. In effect, this is a planar interface between two different structurally chiral materials. Theoretical analysis shows that more than one Dyakonov-Tamm waves, with different phase speeds and degrees of localization to this interface, may propagate in different directions guided by the interface.